BAYONNE, New Jersey (AP) — Passengers aboard a Caribbean cruise ship where almost 700 people fell ill recalled days of misery as it returned to its U.S. home port Wednesday, its trip cut short by what is suspected to be one of the largest norovirus outbreaks in the last 20 years.

Kim Waite, 50, of England was on the Royal Caribbean cruise to celebrate the end of her cancer treatments. She got severely ill.

"There were just hundreds of people being sick everywhere," she said. "They were throwing up in buckets and bags — I started crying, I couldn't believe it. I was in shock."

The U.S. Centers for Disease Control and Prevention said its latest count puts the number of those sickened at 630 passengers and 54 crew members. The Explorer of the Seas was carrying 3,050 passengers.

Health investigators suspect norovirus, but lab results are not expected until later this week. If norovirus is to blame, it would be one of the largest outbreaks on a cruise ship in the last 20 years, the CDC said. A 2006 norovirus outbreak on a Carnival Cruise Lines ship also sickened close to 700.

Bill Rakowicz, 61, of Canada said he thought he was just seasick when he began suffering from vomiting, pain and diarrhea.

"Then I went out of my room and saw people with gloves and people sick everywhere," he said.

Norovirus — once known as Norwalk virus — is highly contagious. It can be picked up from an infected person, contaminated food or water or by touching contaminated surfaces. Sometimes mistaken for the stomach flu, the virus causes bouts of vomiting and diarrhea for a few days.

CDC investigators boarded the ship during its U.S. Virgin Islands port call on Sunday. They said no single food or water source or other origin has been identified.

The ship will be sanitized and no one will be allowed aboard for a period of more than 24 hours as an extra precaution, the cruise line said.

Rick O'Shea from Miami-based ByoPlanet was at the dock to greet the ship. His company was going to use sprayers that produce electrically charged droplets to help sanitize the ship. He said it would take eight to 12 hours to complete the job.

Explorer of the Seas is on track to depart at its originally scheduled time Friday afternoon on its next cruise, a nine-night trip with port calls in Puerto Rico, St. Thomas, the Dominican Republic and Haiti, a Royal Caribbean spokeswoman said.

___

AP Medical Writer Mike Stobbe in Atlanta contributed to this report.